Pump for concrete and other sludging materials

ABSTRACT

A pump for concrete and other sludgy materials comprises a hopper with two parallel pump cylinders connected to the hopper, the open (head) ends of the cylinders opening to the interior of the hopper. A C-shaped discharge pipe is disposed in the hopper with its upper end connected to a delivery pipe which is disposed above the pump cylinders and which has its inlet end facing in the same direction as the head ends of the cylinders. The discharge pipe is oscillated to and fro about an axis above and parallel to the pump cylinders to bring the lower end of the discharge pipe into register with the open ends of the two pump cylinders alternately. Means may be provided for pressing the lower end of the discharge pipe against the open ends of the pump cylinders to minimise leakage.

[451 Aug. 27, 1974 3,465,685 9/1969 Sherrod 3,663,129 5/1972 Ant0sh........ 3,726,614

[5 PUMP FOR CONCRETE AND 0 1 t SLUDGINGMATERIALS 4/1973 Schellenberg...

R25,568 5/1964 Sherrod..........................:...

Karl Schlecht, Bemhausen B. Stuttgart, Germany [75] Inventor:

3 A e [me ho! GmbH Primary Examiner-William L. Freeh [7 1 sslgnee Basel, f dmg Assistant Examiner-G. P. LaPointe Dec. 7, 1972 Attorney, Agent, or Firm-Werner W. Kleeman [22] Filed:

[ ABSTRACT A pump for concrete and other sludgy materials com- [21] App]. N0.: 313,128

prises a hopper with two parallel pump cylinders connected to the hopper, the open (head) ends of the cylinders opening to the interior of the hopper. A C- hopper with its upper end connected to a delivery pipe which is disposed above the pump cylinders and-which has its ders alternately. Means may be provided for pressing the lower end of the discharge pipe against the open ends of the pump cylinders to minimise leakage.

16 Claims 5 Drawing Figures L. .m M 6 m m. o 5 mm 33 an El 0 m mm en a we w 6 mm g .mm b M r m mg 6 df o Wt C.m.m

shaped discharge pipe is disposed in the inlet end facing in the same direction as the head ends of the cylinders. The discharge pipe is oscillated to and fro about an axis above and parallel to the 6 O2 6 0 00 3 4 9 2 55 6 712 b 1 1 2 4 0% m E a s m W mam m W 1m2,9 u 4" t E a a n n u n mm s @A m m n mwus mm aad m m It mam? final l n .m e 2W4 mT mmmm PG wSBSSSW M mm MD 1 HH E75577 F u 56666 1 n wwwww a h M/l/l/ M6 uao U655 7 F d m Std D Uhfi nwwnn m Mum m gonna 3 555 5 q a s2- v [rlll 23333 PATimfmazl'mn 3.832.097

PUMP F OR CONCRETE AND OTHER SLUDGING MATERIALS The invention relates to a pump for concrete and other sludgy materials of the kind having two parallel pump cylinders projecting laterally from the bottom of a hopper or funnel and arranged to deliver the material from the hopper into a discharge pipe which has one of its ends connected to a delivery pipe and which is so mounted in a swivel bearing for movement about an axis substantially parallel to the axes of the pump cylinders that its other end is moved into register with the discharge ends of the two cylinders alternately. The pump cylinders are connected to a rear wall of the hopper.

Swivelling discharge pipes of the aforementioned kind as used in known concrete pumps have approximately the form of a half wave-length of a planar sinusoidal oscillation between two successive peaks so that the axis of the delivery pipe connected to the outlet end of the discharge pipe is displaced longitudinally from, but is parallel to the axes of, the pump cylinders. Such form and arrangement of a discharge pipe not only results in an undesirable increase in length in the overall structure of the pump, but also suffers from the disadvantage that the hopper cannot be charged from an end of the pump but has to be charged from the side, and this makes it difficult to operate a concrete pump in the constricted conditions usually encountered on building sites.

The object of the present invention is to Provide a concrete pump which can be made of compact design such as is required in particular in the case of mobile concrete pumps in which the end of the delivery pipe adjoining the swivelling discharge pipe connection with a delivery mast structure resting on the front part of the chassis. The invention also enables the hopper to be charged without difficulty from the rear end of the vehicle, because a relatively low-level arrangement of the hopper can be achieved. The invention may also facilitate removal and replacement of parts of the mechanism which are subject to heavy wear.

According to the invention, the delivery pipe is disposed above the pump cylinders and has its inlet end facing in the same direction as the open ends of the pump cylinders, and the discharge pipe is Cshaped and is disposed in the hopper, the upper end of the discharge pipe being connected to the delivery pipe and the lower end being connected to the two pump cylinders alternately.

In this arrangement, the swivel bearing of the discharge pipe may be fitted either coaxially with or offcentre from the delivery pipe. A further possible advantageous arrangement of the swivel bearing consists in positioning it on the lower face of a plate which is disposed over the hopper and which serves as a platform. The upper end of the discharge pipe may conveniently be flanged to the delivery pipe with the aid of a quickaction torsion-resisting bolt system. This part of the delivery pipe, constituted by a rigid tube, can be connected, preferably by means of a rotary coupling, to the adjoining part of the delivery pipe secured to the vehicle superstructure.

To enable the discharge pipe to be applied with the necessary pressure to the open end of each pump cylinder or to the appropriate opening in an intermediate member, a hydraulic actuator associated with each of the cylinders may be fitted on the hopper wall and spaced away from the pump cylinders, the piston of each of these hydraulic actuators acting on a pressure boss on the discharge pipe. If may be of advantage if these actuators act only indirectly on the slide pipe, this being achieved by said pistons acting on a transverse rail which is disposed within the hopper and along which slides the pressure, boss on the discharge pipe. Pressure can alternatively be advantageously applied to the slide pipe by causing the ends of such transverse rail to be acted upon by tie rods which extend through the rear wall of the hopper and which are actuated by hydraulic or mechanical tensioning elements which are backed by the rear wall of the hopper. The swivelling discharge pipe can be also pressed on to the open ends of the pump cylinders in a simple manner by utilizing the pressure applied to the working pistons of the pump force applied by the pressure fluid to the working pistons acts on the tie rods.

The portion of the hopper adjacent the rear wall, may advantageously be covered by means of a horizontal plate, for example a close-meshed screen, serving as a platform, while the forward part of the hopper into which the concrete is charged is covered by means of a barred grating which may be replaceable and which holds back any oversize particles of additives. To prevent stiff concrete from building up on the grating at least one lug or projection may advantageously be provided on the discharge pipe and arranged to strike a corresponding stop on the grating, or the grating itself, just before the discharge pipe reaches its end position each time, and thus causes the grating, which may advantageously have slight play in its bearings, to vibrate.

A replaceable wear plate is preferably fitted on the inner face of the rear wall of the hopper in that zone by the lower end of the discharge pipe, A replaceable ring made of a wear-resisting material can also be provided at the lower end of the discharge pipe, this ring also forming a continuous jointing element extending from the pump cylinder to the discharge pipe which may be of smaller diameter than the pump cylinder. In addition, the cross-section of the discharge pipe may taper in the direction of delivery. If the main part of the delivery pipe has a still smaller cross-section, then the delivery pipe may have a section disposed adjacent the discharge pipe and having a continuously tapering crosssection. This section may advantageously be connected by means of a revolving coupling to the adjacent rigid main portion of the delivery pipe.

Some embodiments of the invention are illustrated diagrammatically in the drawings by way of example. In the drawings:

FIG. 1 is a longitudinal sectional view of a pump according to the invention,

FIG. 2 shows a vertical section through the hopper on the line A-B of FIG. 1,

FIG. 3 is a view corresponding to FIG. 1 of a modifled construction,

FIG. 4 is a sectional view on the line C-D of FIG. 3, and

FIG. 5 is another sectional elevation of the pump.

Referring to the drawings, two pumps 1 each have a sleeve 16 having a flange 17 which is connected to a flanged element 9 secured to the rear wall 7 of a hopper 2. Mounted in the side walls of the hopper is a shaft carrying helical mixing blades 11. These blades not only intensively mix the material but also direct it towards the adjacent open ends of the pump cylinders, which are located adjacent the centre line of the hopper. The discharge pipe 4 is mounted in the hopper 2 to swing about a shaft 5, which may have a certain amount of axial play or may be of the universal joint type, to move into register with the adjacent ends of the two pump cylinders alternately. The swinging move ment of the .discharge pipe 4 about the shaft 5 is achieved by means of pivotally mounted hydraulic cylinders 6, the pistons of which are linked with the ends of a rocker 45 embracing the delivery pipe 3. The hopper 2 is closed at the bottom by means of a flap 22 which is mounted on a hinge 23 and which includes sealing strips 24 fitted in grooves. The flap 22 is pressed tightly on to the walls of the hopper with the aid of clamping means 25.

In a manner shown in FIG. 5 but not in FIG. 1 a horizontal plate 41 extends over the hopper and serves as a platform for the person supervising the charging of the hopper. The hopper is charged through a rearwardly and downwardly inclined opening which is covered by a barred grating 43.

To ensure that the lower end of the discharge pipe 4 is pressed tightly on to the annular surfaces surrounding the open ends of the pump cylinders, pressure which acts at right angles to the rear wall 7 of the hopper is applied to the lower end part of the discharge pipe. For this purpose a stop piece 12 is welded on to the lower end part of the discharge pipe, and the piston of a hydraulic actuator 14 presses on to this stop either directly or by way of a transverse rail 13 which bears against the stop. The piston of the hydraulic actuator 14 is preferably so controlled that it acts on the stop 12 only when the discharge pipe 4 is in its end positions. In order to facilitate the swinging movement of the discharge pipe 4, the arrangement may be such that the lower end of the pipe 4 is lifted from the rear wall 7 of the hopper during the swinging movement. In order to prevent wear in that portion of the rear wall disposed between the openings of the pump cylinders, a wear plate 15 is so fitted over this area of the rear wall that it can be readily replaced either laterally or when the flap 22 has been opened.

Hydraulic motor cylinders 18 for reciprocating the pump pistons are flanged on to the water tank 20 in the customary manner by means not illustrated in the drawing, and the rear ends of these cylinders are each closed by a cap 26. The two cylinder caps may be interconnected by means of a transverse bar, not illustrated, and acted upon by intermediate plungers 27 mounted for axial displacement in the motor cylinders 18. By means of these intermediate plungers 27 a tensile force can be applied to the stop 12 on the discharge pipe 4 by way of tie-rods, so that upon each compression stroke of a working piston of the pump cylinders, the required pressure is applied to the lower arm of the pipe-slide by way of the cylinder caps 26 and the rods similar to the tie-rods 21, which are employed in an alternative construction shown in FIG. 4.

The tapering delivery pipe 3, which is connected tov It will be understood that the pump pistons are out of place with each other and that during the backward stroke of one piston to draw concrete from the hopper into the pump cylinder through the open end thereof, the other pump piston is moving forward to discharge the concrete from its cylinder into the discharge pipe 4, which is disposed over the open cylinder end during this time.

In the embodiment illustrated in FIGS. 3 and 4, the clamping means for the discharge pipe 4 is so designed that the transverse rail 13, along which the stop 12 on the pipe 4 slides when the latter is swung, is pressed against the stop 12 by way of tie-rods 21 and the clamping cylinders 30 fitted below the pump cylinders 1. In this arrangement, the tie-rods 21 are supported on the transverse rail 13 by screwed bolts 33 and have watertight seals at' the points where they pass through the rear wall 7 of the hopper 2. The clamping cylinders 30 are supported on the flanges 9 by longitudinal supports 31, or directly on the rear wall 7 of the hopper.

In the embodiment illustrated in FIG. 3, the hydraulic cylinder 6 which imparts the swinging movement to the discharge pipe 4 is disposed substantially horizontally and has a lever which embraces the reducing tube 3 and is linked with the piston of the cylinder.

As will be seen from FIG. 5, a platform 41 with a handrail is disposed above the hopper 2, this platform only overlying the hopper 2 to an extent such that the chute of a mobile concrete mixer can be moved into a position above the rearwardly and downwardly inclined charging orifice of the hopper, which orifice is covered by a barred grating 43. Fitted on the discharge pipe 4 I is a lug 42 which, just before the slidepipe reaches either of its end positions, strikes a stop provided on the grating 43 and so causes the latter to vibrate.

.The lower end of the discharge pipe 4 has a replaceable ring 44 as shown in FIG. 5 which is made of wearresisting material and which is widened out in the form of a cone in a direction towards the wear plate 15.

I claim:

1. A pump for concrete and like sludgy material comprising a hopper, two parallel pump cylinders disposed side by side extending laterally from the hopper and opening at one end to the bottom of the hopper, pump pistons cyclically reciprocally mounted in the respective pump cylinders for drawing said material into said one end of the pump cylinders from the hopper and discharging the material back through said one end, a delivery pipe disposed above the pump cylinders and having an inlet end which faces in the same direction as the said ends of the pump cylinders, a C-shaped discharge pipe disposed in the hopper and having an upper and a lower end whereof the upper end is connected to said inlet end of the delivery pipe, means for oscillating the discharge pipe to and fro, about a pivot axis extending parallel to the pump cylinders, to bring the said lower end of the discharge pipe into register with the said ends of the two cylinders alternately to permit discharge from the pump chamber during the discharge portion of the cycle, and means for cyclically pressing and releasing the lower ends of the C-shaped discharge pipe against the said ends of the pump cylinders during the discharger portion of the cycle to minimize leakage.

2. A pump as claimed in claim 1, wherein the hopper has a rear wall to which the inlet end of the delivery pipe is secured, the said pivot axis of the discharge pipe being coaxial with the inlet end of the delivery pipe.

3. A pump as claimed in claim 1, wherein the hopper has a rear wall to which the inlet end of the delivery pipe is secured, the said pivot axis of the discharge pipe being offset from the delivery pipe.

4. A pump as claimed in claim 1, further comprising an inspection platform above the hopper, and a pivot mounting secured to the platform and supporting the discharge pipe to provide said pivot axis thereof.

5. A pump for concrete and like sludgy material comprising a hopper, two parallel pump cylinders disposed side by side extending laterally from the hopper and opening at one end to the bottom of the hopper, pump pistons reciprocatably mounted in the respective pump cylinders for drawing said material into said one end of the pump cylinders from the hopper and discharging the material back through said one end, a delivery pipe disposed above the pump cylinders and having an inlet end which faces in the same direction as the said ends of the pump cylinders, a C-shaped discharge pipe dis-. posed in the hopper and having an upper and a lower end whereof the upper end is connected'to saidinlet end of the delivery pipe, and means for oscillating the discharge pipe to and fro, about a pivot axis extending parallel to the pump cylinders, to bring the said lower end of the discharge pipe into register with the said ends of the two cylinders alternately, a hydraulic piston and cylinder motor mounted on the hopper in general alignment with but spaced from said end of each of the pump cylinder, which motors are operable to press the lower end of the discharge pipe releasably against the said end of the pump cylinders aligned with the motors.

6. A pump as claimed in claim 5, wherein the pistons of said motors are interconnected by a transversely extending bar which is releasably engageable against the discharge pipe to press said lower end thereof against the said end of either of the pump cylinders.

7. A pump for concrete and like sludgy material comprising a hopper, two parallel pump cylinders disposed side by side extending laterally from the hopper and opening at one end to the bottom of the hopper, pump pistons reciprocatably mounted in the respective pump cylinders for drawing said material into said one end of the pump cylinders from the hopper and discharging the material back through said one end, a delivery pipe disposed above the pump cylinders and having an inlet end which faces in the same direction as the said ends of the pump cylinders, a C-shaped discharge pipe disposed in the hopper and having an upper and a lower end whereof the upper end is connected to said inlet end of the delivery pipe, and means for oscillating the discharge pipe to and fro, about a pivot axis extending parallel to the pump cylinders, to bring the said lower end of the discharge pipe into register with the said ends of the two cylinders alternately, two actuators mounted externally of the hopper adjacent to the respective pump cylinders, two tie bars which are respectively connected to the actuators and which extend into the hopper and are movable lengthwise of themselves by the actuators, and a cross-bar disposed in the hopper and interconnecting the tie bars, which cross-bar is movable by each of the tie bars and the actuator connected thereto to press the lower end of the discharge pipe against the said end of the pump cylinder adjacent such actuator.

8. A pump as claimed in claim 7, wherein the said actuators are connected to be actuated simultaneously with the pump pistons in the respective adjacent pump cylinders.

9. A pump as claimed in claim 8, further comprising two piston and cylinder motors mounted on the other ends of and coaxially with the respective pump cylinders, which motors are connected to reciprocate the pump pistons, and wherein the actuators comprise auxiliary plungers projecting into the cylinder of the respective motors for actuation by pressure fluid supplied 'to the motors, a cross-member being provided which interconnects the plungers.

10. A pump for concrete and like sludgy material comprising a hopper two parallel pump cylinders disposed side by side extending laterally from the hopper and opening at one end to the bottom of the hopper, pump pistons reciprocatably mounted in the respective pump cylinders for drawing said material into said one end of the pump cylinders from the hopper and discharging the material back through said one end, a delivery pipe disposed above the pump cylinders and having an inlet end which'faces in the same direction as the said ends of the pump cylinders, a C-shaped discharge pipe disposed in the hopper and having an upper and a lower end whereof the upper end is connected to said inlet end of the delivery pipe, and means for oscillating the discharge pipe to and fro, about a pivot axis extending parallel to the pump cylinders, to bring the said lower end of the discharge pipe into register with the said ends of the two cylinders alternately, a cover in the form of a grating over the hopper, said grating having elements which are positioned to be struck by the discharge pipe just before the lower end of the discharge pipe comes into register with the said ends of the respective pump cylinders during the movement of the discharge pipe to and fro.

11. A pump as claimed in claim 1, further comprising a wear plate which is mounted in the hopper and which is adapted to be swept by said lower end of the discharge pipe during the latters oscillatory movement.

12. A pump as claimed in claim 1, wherein the discharge pipe has a smaller diameter than the pump cylinders and has a conical end-ring secured on the lower end thereof, which end-ring increases in diameter in a direction towards the said ends of the pump cylinders.

16. The pump as claimed in claim 1, wherein said C- shaped discharge pipe includes an intermediate section between its upper and lower ends, the intermediate section inclining vertically towards the upper portion of the hopper rear wall, the upper and lower ends of said C-shaped section having openings facing rearwardly to provide a discharge path for material being handled which approximates from its inlet at the bottom of said C-shaped discharge pipe to the outlet at the top of said C-shaped discharge pipe. 

1. A pump for concrete and like sludgy material comprising a hopper, two parallel pump cylinders disposed side by side extending laterally from the hopper and opening at one end to the bottom of the hopper, pump pistons cyclically reciprocally mounted in the respective pump cylinders for drawing said material into said one end of the pump cylinders from the hopper and discharging the material back through said one end, a delivery pipe disposed above the pump cylinders and having an inlet end which faces in the same direction as the said ends of the pump cylinders, a C-shaped discharge pipe disposed in the hopper and having an upper and a lower end whereof the upper end is connected to said inlet end of the delivery pipe, means for oscillating the discharge pipe to and fro, about a pivot axis extending parallel to the pump cylinders, to bring the said lower end of the discharge pipe into register with the said ends of the two cylinders alternately to permit discharge from the pump chamber during the discharge portion of the cycle, and means for cyclically pressing and releasing the lower ends of the C-shaped discharge pipe against the said ends of the pump cylinders during the discharger portion of the cycle to minimize leakage.
 2. A pump as claimed in claim 1, wherein the hopper has a rear wall to which the inlet end of the delivery pipe is secured, the said pivot axis of the discharge pipe being coaxial with the inlet end of the delivery pipe.
 3. A pump as claimed in claim 1, wherein the hopper has a rear wall to which the inlet end of the delivery pipe is secured, the said pivot axis of the discharge pipe being offset from the delivery pipe.
 4. A pump as claimed in claim 1, further comprising an inspection platform above the hopper, and a pivot mounting secured to the platform and supporting the discharge pipe to provide said pivot axis thereof.
 5. A pump for concrete and like sludgy material comprising a hopper, two parallel pump cylinders disposed side by side extending laterally from the hopper and opening at one end to the bottom of the hopper, pump pistons reciprocatably mounted in the respective pump cylinders for drawing said material into said one end of the pump cylinders from the hopper and discharging the materiaL back through said one end, a delivery pipe disposed above the pump cylinders and having an inlet end which faces in the same direction as the said ends of the pump cylinders, a C-shaped discharge pipe disposed in the hopper and having an upper and a lower end whereof the upper end is connected to said inlet end of the delivery pipe, and means for oscillating the discharge pipe to and fro, about a pivot axis extending parallel to the pump cylinders, to bring the said lower end of the discharge pipe into register with the said ends of the two cylinders alternately, a hydraulic piston and cylinder motor mounted on the hopper in general alignment with but spaced from said end of each of the pump cylinder, which motors are operable to press the lower end of the discharge pipe releasably against the said end of the pump cylinders aligned with the motors.
 6. A pump as claimed in claim 5, wherein the pistons of said motors are interconnected by a transversely extending bar which is releasably engageable against the discharge pipe to press said lower end thereof against the said end of either of the pump cylinders.
 7. A pump for concrete and like sludgy material comprising a hopper, two parallel pump cylinders disposed side by side extending laterally from the hopper and opening at one end to the bottom of the hopper, pump pistons reciprocatably mounted in the respective pump cylinders for drawing said material into said one end of the pump cylinders from the hopper and discharging the material back through said one end, a delivery pipe disposed above the pump cylinders and having an inlet end which faces in the same direction as the said ends of the pump cylinders, a C-shaped discharge pipe disposed in the hopper and having an upper and a lower end whereof the upper end is connected to said inlet end of the delivery pipe, and means for oscillating the discharge pipe to and fro, about a pivot axis extending parallel to the pump cylinders, to bring the said lower end of the discharge pipe into register with the said ends of the two cylinders alternately, two actuators mounted externally of the hopper adjacent to the respective pump cylinders, two tie bars which are respectively connected to the actuators and which extend into the hopper and are movable lengthwise of themselves by the actuators, and a cross-bar disposed in the hopper and interconnecting the tie bars, which cross-bar is movable by each of the tie bars and the actuator connected thereto to press the lower end of the discharge pipe against the said end of the pump cylinder adjacent such actuator.
 8. A pump as claimed in claim 7, wherein the said actuators are connected to be actuated simultaneously with the pump pistons in the respective adjacent pump cylinders.
 9. A pump as claimed in claim 8, further comprising two piston and cylinder motors mounted on the other ends of and coaxially with the respective pump cylinders, which motors are connected to reciprocate the pump pistons, and wherein the actuators comprise auxiliary plungers projecting into the cylinder of the respective motors for actuation by pressure fluid supplied to the motors, a cross-member being provided which interconnects the plungers.
 10. A pump for concrete and like sludgy material comprising a hopper two parallel pump cylinders disposed side by side extending laterally from the hopper and opening at one end to the bottom of the hopper, pump pistons reciprocatably mounted in the respective pump cylinders for drawing said material into said one end of the pump cylinders from the hopper and discharging the material back through said one end, a delivery pipe disposed above the pump cylinders and having an inlet end which faces in the same direction as the said ends of the pump cylinders, a C-shaped discharge pipe disposed in the hopper and having an upper and a lower end whereof the upper end is connected to said inlet end of the delivery pipe, and means for oscillating the discharge pipe to and fro, about a pivot axis extending parallel to the pUmp cylinders, to bring the said lower end of the discharge pipe into register with the said ends of the two cylinders alternately, a cover in the form of a grating over the hopper, said grating having elements which are positioned to be struck by the discharge pipe just before the lower end of the discharge pipe comes into register with the said ends of the respective pump cylinders during the movement of the discharge pipe to and fro.
 11. A pump as claimed in claim 1, further comprising a wear plate which is mounted in the hopper and which is adapted to be swept by said lower end of the discharge pipe during the latter''s oscillatory movement.
 12. A pump as claimed in claim 1, wherein the discharge pipe has a smaller diameter than the pump cylinders and has a conical end-ring secured on the lower end thereof, which end-ring increases in diameter in a direction towards the said ends of the pump cylinders.
 13. A pump as claimed in claim 1, wherein the discharge pipe has a tapering diameter from its lower to its upper end.
 14. A pump as claimed in claim 1, wherein the delivery pipe has a diameter which tapers in a direction away from the discharge pipe.
 15. A pump as claimed in claim 1, wherein the delivery pipe includes an upstream section which is secured to the upper end of the discharge pipe, and a fixed downstream section, and wherein a rotatable coupling interconnects the upstream and downstream sections.
 16. The pump as claimed in claim 1, wherein said C-shaped discharge pipe includes an intermediate section between its upper and lower ends, the intermediate section inclining vertically towards the upper portion of the hopper rear wall, the upper and lower ends of said C-shaped section having openings facing rearwardly to provide a discharge path for material being handled which approximates 180* from its inlet at the bottom of said C-shaped discharge pipe to the outlet at the top of said C-shaped discharge pipe. 